1000kV特高压变电构架风荷载特性

Wind load characteristics of 1 000 kV UHV substation frame

利用1000 kV特高压变电构架在均匀流、A类和B类地貌高频底部测力天平风洞试验同步测量的基底弯矩和反力的时程数据,对变电构架整体及节段模型的气动力系数功率谱以及均值、均方根、峰度和偏度等统计特性对比分析,详细考察风向、地貌等因素对风荷载特性的影响规律并探讨不同流场下输电构架整体与节段模型的气动力特性比例关系。研究结果表明:以A节段模型为例,0°风向均匀流场、A类和B类地貌下C x均值和均方根值之比分别为1∶1.58∶1.57和1∶1.60∶1.59,与之对应,C y均值和均方根值之比分别为1∶7.00∶7.57和1∶1.53∶1.30.整体和各节段模型对比分析发现,90°风向均匀流场下整体模型与四个节段模型C x的均值和均方根值之比分别为1∶0.02∶0.26∶0.22∶0.38和1∶0.06∶0.37∶0.32∶0.41,C y的均值和均方根值之比分别为1∶0.46∶0.57∶0.43∶0.69和1∶0.47∶0.58∶0.44∶0.70.基于时域和频域的综合对比分析明确1000 kV特高压变电构架的最不利风向角以及设计风荷载的取值,为工程设计提供参考。

With time series data of base bending moments and forces simultaneously measured by high frequency force balance(HFFB)wind tunnel test of 1000 kV ultra-high voltage(UHV)substation frame in uniform flow,terrain A,and terrain B,the power spectrum density(PSD)and statistical characteristics such as mean value,root mean square(RMS),kurtosis,and skewness of aerodynamic coefficients of the whole substation frame and segment models were compared and analyzed.The influence rules of wind direction,terrain type,and other factors on the wind load characteristics were investigated,and the proportional relationship of aerodynamic force coefficient characteristic between the overall model and segment models of the substation structure under different flow fields was discussed.Results show that taking segment model A as an example,the ratio of mean values of C x in uniform flow field,terrain A,and terrain B landforms at 0°wind direction was 1∶1.58∶1.57 and that of its RMS values was 1∶1.60∶1.59.Correspondingly,the ratios of mean values and RMS values of C y were 1∶7.0∶7.57 and 1∶1.53∶1.30,respectively.Contrastive analysis of the overall model and various segment models demonstrates that in the uniform flow field at 90°wind direction,the ratios of mean values and RMS values of C x for the overall model and four segment models were 1∶0.02∶0.26∶0.22∶0.38 and 1∶0.06∶0.37∶0.32∶0.41,respectively.While the ratios of mean values and RMS values of C y were 1∶0.46∶0.57∶0.43∶0.69 and 1∶0.47∶0.58∶0.44∶0.70,respectively.The most unfavorable wind direction and design wind load of 1000 kV UHV substation frame were determined by comprehensive comparative analysis of time and frequency domains,which provides reference for engineering design.